Method and apparatus for cooling transducers



Sept. 6, 1955 F. P. BUNDY METHOD AND APPARATUS FOR COOLING TRANSDUCERS Filed May 27, 1954 In venzror;

Francis PBundy, b g/ d. m His Attorney.

United States Patent METHOD AND APPARATUS FUR COOLING TRANSDUCERS Francis P. Bundy, Alplaus, N. Y., assignor to General Electric Conipanyfa corporation of New York Application May 27, 1954, Serial No. 432,752 11 Claims. (Cl. 310-16) This invention relates to transducers and specifically to a method and apparatus for cooling continuously operative high-power transducers.

High-power transducers, which are capable of continuous operation for a prolonged period of time, are desirable in such operations as the cleaning of plate glass and the tinning of aluminum. No serious cooling problem is encountered in low-power transducers nor in transducers to which high power is applied in short pulses with relatively long cooling periods between pulses. Under such operating conditions, layers or pads of cushioning material are cemented to the non-radiating surfaces of the transducer element. However, such materials are inherently good thermal insulators in that they impede the flow of heat from the transducer element. Conventional cushioning pads are unsuitable in those situations in which it is desirable to constantly operate a high-power transducer for a prolonged period.

Accordingly, it is an object of my invention to provide an improved high-power transducer structure in which a fluid coolant is employed.

It is another object of the invention to provide an improved high-power transducer structure in which a fluid coolant directly contacts the'transducer element.

It is another object of the invention to provide an improved high-power transducer structure in which an acoustic cushioning fluid is the cooling medium.

It is a further object of the invention to provide a novel method of v continuously cooling a continuously operative high-power transducer.

In carrying out my invention in one form, an aerated acoustic cushioning fluid is circulated in direct thermal contact with a transducer element to provide the cooling medium therefor.

These and various other objects, features and advantages of the invention will be better understood from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a sectional view of an embodiment of my invention as applied to an individual transducer structure in which a fluid coolant is employed;

Fig. 2 is a diagrammatic view of a transducer structure with a modified fluid cooling system;

Fig. 3 is a partial sectional view of a transducer structure with a further modified fluid cooling system; and

Fig. 4 is a perspective view of a series of transducers such as those shown in Fig. 1 which are mounted in a staggered array for cleaning an extensive surface of glass.

Fig. 1 of the drawing discloses an individual transducer structure which comprises a liquid-tight housing to define a chamber 11 wherein a transducer element 12 is mounted. The housing may also be of any suitable construction which will provide a fluid passage adjacent the element 12. The transducer element 12 consists of a core 13 of a laminated magnetostrictive material which has windings 14 thereon. An active to remove the cooling fluid from the chamber 11.

;; to form a circulatory passage for the cooling fluid.

vibrating face 15 of the core 13 is firmly bonded to a resilient face 16 to transmit compressional waves from the core 13 to a workpiece (not shown) outside the housing 10. The face 16, which may be composed of a suitable material, such as, for example, rubber or plastic will provide the bottom wall for this housing. A pair of wires 17 connect the windings 14 to an A. C. power source (not shown) through a sealed wire terminal 18 in the top wall of the housing 10.

A cooling fluid inlet 19 and a fluid outlet 20 are provided in the side andtop walls of the housing Ill, respectively. An inlet tube or circulation line 21 is connected to the fluid inlet 19 to circulate a cooling fluid from a centrifugal pump 22 to the interior of the chamber 11. An inert gas, such as, for example, air is admitted to the fluid through a nozzle 23 from a gas source (not shown) for reasons to be described hereinbelow. An outlet tube or circulation line 24, which has a gas vent 25 therein, is connected to the outlet 20 A heat exchanger 26 is provided in the line 24 to remove the excess heat from the cooling fluid which heat may be transferred to a secondary fluid medium. If it is desired, the tube 24 may be connected to the pump 22 A valve 27 may also be provided in the line 24 to regulate the flow of the fluid to the pump 22.

The cooling fluid is provided with a stable suspension of small inert gas bubbles to impart an acoustic cushioning property thereto thereby eliminating the conventional heat-insulating, cushioning pads which surround the non-radiating surfaces of the transducer element. The cooling fluid should be an electric non-conducting, non-corroding, non-damping and chemically stable liquid. Satisfactory materials, which fulfill these requirements, are transformer oils, and liquid dielectrics, such as, for example, pyranol.

In operation, the cooling fluid is circulated by the centrifugal pump 22 through the tube 21 and the inlet 19 into direct thermal contact with the transducer element 12 within the chamber 11. Thegas nozzle 23 provides a stable suspension of gas bubbles for the cooling fluid. After the fluid absorbs the heat from the transducer element, it passes through the outlet 20, tube 24, heat exchanger 26, and regulating valve 27 to the inlet side of the pump 22. The excess heat of the fluid is removed by the heat exchanger 26 while gas is permitted to escape through the vent 25.

Fig. 2 discloses a modified cooling system for a trar ducer structure which employs a mechanical fluid agitator 28 to churn the cooling fluid. The agitation of the cooling fluid whips the gas, which is admitted through the nozzle 23 in the line 21, into the cooling fluid in the form of a stable suspension of gas bubbles.

Fig. 3 discloses a further modified form of fluid cooling system for a transducer structure wherein the cooling fluid is circulated to the chamber 11 of the housing 10 through an inlet tube 29. The inlet tube 29 is connected to the pump 22 in a similar manner to the tube 21 which is disclosed in Fig. 1. A gas injection jet 30 with a reversed L-shape is provided in the tube 29 to admit gas bubbles to the cooling fluid. The tube 29 is provided with a venturi 31 near the exit of the jet 30 to promote a stable gas suspension. The air injection jet 30 may also be used to circulate the cooling fluid thereby eliminating the pump 22.

Fig. 4 shows a plurality of transducers of the type described above with reference to Fig. l which are mounted in a staggered array for cleaning extensive surfaces, such as, for example, plate glass or metal. The housings 10 are arranged in two staggered longitudinal rows between supporting beams 32 which may form part of a frame member (not shown). Each housing 10 is mounted to its adjacent supporting beams 32 by means of angle brackets 33 which are suitably secured to both the housing and the support, such as, for example, by welding or by screws. The fluid inlet tubes 21 and outlet tubes 24 of the housing 10 may be connected to inlet and outlet manifolds, respectively.

A sheet of glass 34 which has a film of water thereon is passed underneath the resilient faces 16 of the housings 10. The film of water, which is in contact with outer surfaces of the faces 16, transmits vibrations from these faces to clean the glass surface. A plurality of rows of transducer structures may be provided rather than the two rows shown in Fig. 4.

As it will be apparent to those skilled in the art, the objects of my invention are attained by the use of an aerated, electric non-conducting and non-damping cooling fluid which is circulated in direct thermal contact with a transducer element.

While other modifications of this invention and variations of apparatus which may be employed within the scope of the invention have not been described, the invention is intended to include all such as may be ernbraced within the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for cooling a transducer having a transducer element, which comprises a housing to surround said element, and means for circulating an aerated acoustic cushioning fluid in said housing in direct thermal contact with said element.

2. Apparatus for cooling a transducer having a transducer element, which comprises a housing to surround said element, and an aerated acoustic cushioning fluid in said housing in direct thermal contact with said element.

3. Apparatus for cooling a transducer having a transducer element, which comprises a housing to surround said element, an aerated cushioning fluid in said housing in direct thermal contact with said element, and means to circulate said fluid.

4. A transducer comprising a housing defining a chamber, at least one transducer element within said housing, an electric non-conducting and non-damping cooling fluid within said chamber, means to aerate said fluid, and means to circulate said fluid through said chamber in direct thermal contact with said element.

5. A transducer comprising a housing defining a chamber, a transducer element within said housing, an electric non-conducting and non-damping cooling fluid 4 within said chamber, and means to aerate and circulate said fluid through said chamber in direct thermal contact with said element.

6. A transducer comprising a housing defining a chamber, a transducer element arranged within said housing, inlet means to provide a passage to the interior of said chamber, outlet means to provide a passage from said chamber, and means for circulating an electric non-conducting and non-damping aerated cooling fluid through said inlet tube, said chamber in direct thermal contact with said elements, and said outlet tube.

7. A transducer comprising a housing defining a chamber, a transducer element arranged within said housing, an inlet tube to provide a passage to the interior of said chamber, an outlet tube to provide a passage from said chamber, an electric non-conducting and non-damping cooling fluid in said chamber in direct thermal contact with said element, said fluid having a stable suspension of inert gas bubbles therein, and means for circulating said fluid through said inlet tube, chamber and outlet tube.

8. The method of cooling a transducer having a transducer element which comprises aerating an electric nonconducting and non-damping fluid, and circulating said 1 fluid in direct thermal contact with said transducer element.

9. The method of cooling a transducer having a transducer element which comprises agitating an electric nonconducting and non-damping fluid, incorporatlng a stable suspension of inert gas bubbles therein, and circulating said fluid in direct thermal contact with said transducer element.

10. The method of cooling a transducer having a transducer element and a housing which comprises aerating an electric non-conducting and non-damping fluid, and circulating said fluid through said housing in direct thermal contact with said transducer element.

11. The method of cooling a transducer having a transducer element and a housing which comprises agitating an electric non-conducting and non-damping fluid, incorporating a stable suspension of inert gas bubbles therein, and circulating said fluid through said housing in direct thermal contact with said transducer element.

Rodman Dec. 10, 1929 Camilli et al. May 4, 1948 

